Catheter for monitoring uterine contraction pressure

ABSTRACT

A multi-lumen catheter for monitoring uterine contraction pressure having an elongated body configured and dimensioned for insertion into a bladder of a patient, the catheter having a first lumen, a second lumen, and a first balloon at a distal portion, the first lumen communicating with the first balloon. The second lumen communicates with the bladder to remove fluid from the bladder. The first balloon is filled with a gas to form along with the first lumen a gas filled chamber to monitor pressure within the bladder to thereby monitor uterine contraction pressure of the patient.

This application claims the benefit of provisional application Ser. No.62/544,690, filed Aug. 11, 2017, provisional application Ser. No.62/514,793, filed Jun. 3, 2017, provisional application Ser. No.62/590,513, filed Nov. 24, 2017 and provisional application Ser. No.62/622,871, filed Jan. 27, 2018. The entire contents of each of theseapplications are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This application relates to a device and method for monitoring uterinecontraction pressure through the urinary bladder.

2. Background

Traditionally, recording of uterine contraction has been performedthrough tocodynamometry, a strain gauge technology for measuring uterinecontractions. The tocodynamometer is a transducer strapped onto themother's abdomen in the area of the uterine fundus (typically around 10cm above or below the umbilicus). This externally placed transducer hasa tendency to become loose or fall off the maternal abdomen. Thus, ithas to be periodically readjusted in order to record contractions. Also,this external transducer only measures the frequency and duration of theuterine contractions. Thus, it is limited since it does not measure thestrength of uterine contraction pressure (UCP). Often accurate pressuremeasurement of uterine contraction is needed to determine adequacy oflabor or the intensity of pre-term labor.

One product currently on the market available to accurately measure theUCP is the Intra-uterine Pressure Catheter (IUPC), a product offered byseveral large companies. The IUPC is placed in the uterus and measuresthe strength of the uterine contraction and makes a continuous recordingon a bedside monitor. Labor induction or labor augmentation is utilizedin about 20% of deliveries. Commonly during labor augmentation, the IUPCis needed to better quantify the intensity of uterine contractions, asexplained in “Dystocia and Augmentation of Labor”, ACOG PracticeBulletin, no. 49, Washington, D.C., American College of Obstetriciansand Gynecologists, December 2003: 1445-54. The IUPC measures pressure byinsertion of the catheter directly into the uterus. Original IUPCs useda column of water to measure pressure and required skilled personnel forsetup. In the late 1980's, intra-uterine pressure catheters with anelectronic sensor were developed which were easier to use and moreaccurate, as explained in “Monitoring Intrauterine Pressure DuringActive Labor. A Prospective Comparison of Two Methods”, Devoe, L D. etal., J Reprod. Med. October 1989, 34(10):811-4. Shortly after, an IUPCwith an air column to measure uterine contraction pressure wasintroduced. Thus, IUPCs currently employed measure uterine contractionpressure using various type of mechanisms such as a column of water, acolumn of air, or an electronic sensor.

While the monitoring of uterine contraction pressure using the foregoingdevices is widely used and under proper circumstances can producereliable measurements, there are a number of disadvantages associatedwith their use. Current IUPCs need to be inserted into the uterusthrough the cervix. The prerequisites for insertion of IUPCs aretherefore: 1) the amniotic membrane has to be ruptured; 2) the cervixhas to be dilated to allow the insertion of the IUPC; and 3) a trainedmedical personal is required to insert the IUPC. Another disadvantage ofusing current IUPCs is that they increase the risk of infection to themother and baby. In an article, “Use of Intrauterine Pressure Catheter(IUPC) Increases Risk of Post-Cesarean Surgical Site Infection”, Rood,Kara M., et al., Obstetrics & Gynecology: May 2017, 129:22.5, it wasnoted that laboring women undergoing cesarean delivery in whom the IUPCwas used were at increased risk of post-cesarean surgical siteinfection. IUPC insertion can also cause severe complications such asplacental abruption and anaphylactoid syndrome leading to maternaland/or fetal morbidity or death.

In addition to the traditional IUPC and the external tocodynamometrycatheter, a device has been recently introduced on the market to measurethe uterine contractions through detection of uterine electricalcurrent. This method is called Electrohysterography (EHG). It has beenshown by Euliano, et al. in “Monitoring Uterine Activity During Labor: AComparison of 3 Methods”, Am. J. Obstet, Gynec. January 2013 208 (1):66,1-6, that EHG is a reliable noninvasive way to measure uterinecontraction similar to the external tocodynamometry catheter. However,it is not able to quantitatively measure the force of the contraction.Another device being used is a disposable external tocodynamometrycatheter by Clinical Innovations that utilizes an air charged system tomeasure contractions. Like the traditional external Tocodynamometry,this device is not able to quantify the force of the contractions.

It would be advantageous to provide a catheter that does not require theprerequisites described above for IUPCs, thus avoiding the need for theuterine cervix to be dilated or the amniotic membrane to be ruptured. Itwould also be advantageous if such uterine contraction pressuremeasuring catheters could measure core body temperature as well as drainurine from the bladder. There is also a need for such catheter todiminish the risks of infection to the mother or the baby associatedwith the prior and current use of IUPCs.

It would also be advantageous to provide a catheter capable ofquantifying intensity of uterine contraction in non-laboring mothers andto accurately detect contraction in the mother with symptoms of pretermlabor. Furthermore, it would be advantageous if such device couldcontinuously measure pressure without interruption. This wouldadvantageously enable a constant monitoring of uterine contractionpressure so critical time periods are not missed. It would further beadvantageous to provide a device that improves the accuracy of thepressure reading to more accurately determine uterine contractionpressure.

Still further, it would be advantageous if such catheter could satisfythe foregoing needs and provide these above enumerated advantages whilebeing simple to use so that any of the clinical staff with basicknowledge of bladder catheter insertion will be able to insert thedevice without relying on specially trained staff members, therebyreducing time and expense.

SUMMARY

It has been well known and validated that urinary bladder pressuredirectly correlates to intra-uterine pressure. Gravid uterus is anintra-abdominal organ in direct contact with the urinary bladder. Thus,the pressure generated by uterine contraction directly exerts pressureon the urinary bladder. Utilizing this correlation, the devices of thepresent invention measure bladder pressure to determine uterinecontraction pressure (UCP), with measurement done in various ways,including the ways described in pending provisional application Ser. No.62/514,793, filed Jun. 3, 2017, the entire contents of which areincorporated herein by reference.

The devices of the present invention do not require the insertionprerequisites described above for the current IUPC catheters, i.e., theydo not require the uterine cervix to be dilated nor require rupture ofthe amniotic membranes.

The devices of the present invention can be easily inserted by thenurse, midwife, or a physician taking care of the laboring motherwithout requiring additional training or requiring a physician ortrained staff skilled in insertion of the IUPC catheter. Since mostmothers in active labor require a bladder catheter for drainage ofurine, the catheters can be used to drain the bladder while alsoaccurately measuring UCP without adding any risks to the mother or thebaby. That is, the devices of the present invention can also drain urinefrom the bladder like ordinary bladder catheters.

The devices of the present invention in some embodiments are also ableto measure core body temperature, fetal heart rate and/or maternal pulseoximetry (PO2).

The present invention therefore overcomes the deficiencies anddisadvantages of the prior art. The present invention advantageouslyprovides a multi-lumen catheter insertable into the bladder in the samemanner as a regular bladder drainage catheter to determine uterinecontraction pressure without requiring insertion of water into thebladder. The catheters of the present invention utilize a gas, e.g.,air, charged chamber to measure bladder pressure across a large surfacearea, and thus, accurately determine uterine contraction pressure, andenable pressure to be measured continuously without interrupting urineflow and without interruptions to add water to the bladder.

Some embodiments of the catheter of the present invention utilize inaddition to the pressure balloon a stabilizing balloon to help retainthe catheter in the bladder during the procedure. These embodiments arediscussed in more detail herein.

Various types of sensors are utilized with the several embodiments ofthe catheters of the present invention. For example, in someembodiments, the sensor measures both temperature and pressure; in otherembodiments a separate sensor for measuring pressure and for measuringtemperature are provided. Additionally, different locations for thesensors are disclosed. Each of these various embodiments is discussed indetail herein.

In accordance with one aspect of the present invention, a multi-lumencatheter for monitoring uterine contraction pressure is provided. Thecatheter comprises an elongated body configured and dimensioned forinsertion into a bladder of a patient, the catheter having a firstlumen, a second lumen, and a first balloon at a distal portion. Thefirst lumen communicates with the first balloon and the second lumencommunicates with the bladder to remove fluid from the bladder. Thefirst balloon is filled with a gas to form along with the first lumen agas filled chamber to monitor pressure within the bladder to therebymonitor uterine contraction pressure of the patient. A pressure sensormeasures pressure about a circumferential area of the balloon, thepressure sensor continuously measuring pressure of the bladder toprovide continuous readings of bladder pressure.

In accordance with another aspect of the present invention, amulti-lumen catheter for monitoring uterine contraction pressure isprovided. The catheter comprises an elongated body configured anddimensioned for insertion into a bladder of a patient, the catheterhaving a first lumen, a second lumen, an outer balloon at a distalportion and an inner balloon within the outer balloon. The first lumencommunicates with the inner balloon and the second lumen communicateswith the bladder to remove fluid from the bladder, the inner balloon andfirst lumen filled with a gas to form a gas filled chamber to monitorpressure within the bladder to thereby monitor uterine contractionpressure of the patient. The outer balloon has a circumferential areagreater than a circumferential area of the inner balloon and filled witha gas, e.g., air, wherein in response to pressure within the bladderexerted on an outer wall of the outer balloon, the outer balloon deformsand exerts a pressure on an outer wall of the inner balloon to deformthe inner balloon and compress the gas within the inner balloon and thefirst lumen, the pressure sensor measuring bladder pressure based on gascompression caused by deformation of the inner balloon.

In accordance with another aspect of the present invention, amulti-lumen catheter for monitoring uterine contraction pressure isprovided. The catheter comprises an expandable outer balloon at a distalportion of the catheter, an expandable inner balloon positioned withinthe outer balloon and a first lumen communicating with the innerballoon. The inner balloon and first lumen form a gas, e.g., air, filledchamber to monitor pressure within the bladder to thereby monitoruterine contraction of the patient, wherein the outer balloon has acircumferential area greater than a circumferential area of the innerballoon, wherein in response to pressure within the bladder exerted onthe first outer wall of the expanded outer balloon, the outer balloondeforms and exerts a pressure on the second outer wall of the expandedinner balloon to deform the inner balloon and compress the gas withinthe inner balloon and the first lumen to provide a finer measurement. Asecond lumen communicates with the bladder to remove fluid from thebladder. An external pressure transducer is connectable to the catheterand communicates with the gas filled chamber for measuring bladderpressure based on gas compression caused by deformation of the expandedinner balloon deformed by the expanded outer balloon.

In accordance with another aspect of the present invention, amulti-lumen catheter for monitoring uterine contraction pressure isprovided. The catheter comprises a distal balloon at a distal portion ofthe catheter and a first lumen communicating with the distal balloon.The distal balloon and first lumen form a gas, e.g., air, filled chamberto monitor pressure within the bladder to thereby monitor uterinecontraction pressure of the patient, wherein in response to pressurewithin the bladder the distal balloon deforms to compress the gas withinthe distal balloon. The first lumen has a first proximal portcommunicating with the first lumen. A second lumen communicates with thebladder to remove fluid from the bladder. A temperature sensor ispositioned in a third lumen of the catheter and has a wire extendingthrough the third lumen. A hub is connectable to the first port of thecatheter. The hub includes a pressure transducer for measuring pressurebased on gas compression within the first lumen, wherein connection ofthe hub to the first port automatically connects the wire to anelectrical connector in the hub for connection to a temperature monitor.

In accordance with another aspect of the present invention, amulti-lumen catheter for monitoring uterine contraction pressure isprovided. The catheter comprises a distal balloon at a distal portion ofthe catheter and a first lumen communicating with the distal balloon.The distal balloon and first lumen form an air filled chamber to monitorpressure within the bladder to thereby monitor uterine contractionpressure of the patient, wherein in response to pressure within thebladder the distal balloon deforms to compress the air within the distalballoon. The first lumen has a first proximal port communicating withthe first lumen. A second lumen communicates with the bladder to removefluid from the bladder. A hub is connectable to the first port of thecatheter, the hub including a pressure transducer for measuring pressurebased on air compression with the first lumen. An elongated memberextends distally from the hub, wherein connection of the hub to thefirst port automatically inserts the elongated member into the firstlumen to advance air through the first lumen to expand the distalballoon, the first lumen not vented to atmosphere when the hub isconnected to the first port.

In accordance with another aspect of the present invention, a method formeasuring uterine contraction pressure is provided comprising the stepsof a) providing a catheter having first and second lumens, an expandablefirst balloon, an expandable second balloon positioned over the firstballoon, and a temperature sensor; b) inserting the catheter into abladder of a patient; c) connecting a hub containing a pressuretransducer to the catheter to automatically advance air through thefirst lumen of the catheter to expand the first balloon from a deflatedcondition to a more expanded condition; d) obtaining a first pressurereading of the bladder based on deformation of the first balloon causedby deformation of the second balloon in response to bladder pressureexerted on the second balloon; e) transmitting the first pressurereading to an external monitor connected to the hub, the first pressurereading providing an indicator of uterine contraction pressure; f)obtaining a second pressure reading of the bladder based on deformationof the first balloon caused by deformation of the second balloon inresponse to bladder pressure exerted on the second balloon; and g)transmitting the second pressure reading to the external monitorconnected to the hub, the second pressure reading providing an indicatorof uterine contraction pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those having ordinary skill in the art to which the subjectinvention appertains will more readily understand how to make and usethe surgical apparatus disclosed herein, preferred embodiments thereofwill be described in detail hereinbelow with reference to the drawings,wherein:

FIG. 1A is a side view of a first embodiment of the catheter of thepresent invention having a pressure balloon, a stabilizing balloon and asensor positioned in the air lumen, both balloons shown in the deflated(collapsed) condition;

FIG. 1B is a side view similar to FIG. 1A showing the two balloons inthe inflated (expanded) condition;

FIG. 2 is a schematic view of the system utilizing the catheter of FIG.1A with an alarm system;

FIG. 3 is a close-up view of the tip of the catheter of FIG. 1A;

FIG. 4 is a close-up view of the sensor of FIG. 1 within the air lumen;

FIG. 5 is an enlarged transverse cross-sectional view of the catheter ofFIG. 1A;

FIG. 6 is an enlarged transverse cross-sectional view of an alternateembodiment of a catheter of the present invention having four lumens;

FIG. 7 is a side view of an alternate embodiment of the catheter of thepresent invention similar to FIG. 1 except having a single balloon, theballoon shown in the inflated condition,

FIGS. 8A and 8B are side views of an alternate embodiment of thecatheter of the present invention having two balloons and a pressuresensor and a separate temperature sensor in the air lumen, the twoballoons shown in the deflated condition, with FIG. 8A showing thedistal end and FIG. 8B showing the proximal end of the catheter;

FIG. 9 is a side view similar to FIG. 8A showing the two balloons in theinflated condition;

FIG. 10A is a close up view of the distal portion of the catheter ofFIG. 8A;

FIG. 10B is an enlarged transverse cross-sectional view of the catheterof FIG. 8A;

FIG. 11 is a side view of another alternate embodiment of the catheterof the present invention having two balloons, a sensor in the air lumenand an external transducer, the two balloons shown in the inflatedcondition;

FIG. 12 is a side view of another alternate embodiment of the catheterof the present invention having two balloons, a temperature sensor inthe air lumen and the pressure sensor external of the catheter, the twoballoons shown in the inflated condition;

FIG. 13A is a side view of another alternate embodiment of the catheterof the present invention having two balloons and a pressure sensorpositioned within the pressure balloon, the two balloons shown in theinflated condition;

FIG. 13B is an enlarged view of the distal portion of the catheter ofFIG. 13A;

FIG. 14A is a side view of another alternate embodiment of the catheterof the present invention having dual pressure sensors, the first sensorpositioned within the air lumen and the second sensor positionedexternal of the catheter, the two balloons shown in the inflatedcondition;

FIG. 14B is an enlarged view of the distal portion of the catheter ofFIG. 14A;

FIG. 15 is a side view of another alternate embodiment of the catheterof the present invention having an outer and inner pressure balloon anda stabilizing balloon, the balloons shown in the inflated condition;

FIG. 16 is a side view similar to FIG. 15 illustrating an alternateembodiment having a larger outer balloon;

FIG. 17A is a side view similar to FIG. 15 illustrating an alternateembodiment having a pear-shaped outer balloon;

FIG. 17B is a side view similar to FIG. 17A showing an alternateembodiment wherein the drainage opening is between the stabilizing andpressure balloons;

FIG. 18A is a side view of another alternate embodiment of the catheterof the present invention having a port for connection of an externalpressure transducer and an outer and inner pressure balloon, the twoballoons shown in the inflated condition;

FIG. 18B is close up view of the distal end of the catheter of FIG. 18A;

FIG. 19 is a perspective view of the catheter of FIG. 18A with apressure transducer hub attached to the catheter;

FIGS. 20A, 20B and 20C are enlarged front, side and perspective views ofthe outer balloon of FIG. 18A in the expanded condition;

FIGS. 21A, 21B and 21C are enlarged front, side and perspective views ofthe stabilizing balloon of FIG. 18A in the expanded condition;

FIGS. 22A, 22B and 2C are enlarged front, side and perspective views ofthe inner balloon of FIG. 18A in the expanded condition;

FIG. 23 is a transverse cross-sectional view of the catheter of FIG. 18Aillustrating the five lumens of the catheter;

FIG. 24A is a cutaway side view showing the pressure transducer hubprior to connection to the catheter of FIG. 18A, a portion of the hubwall and catheter connector removed to show internal components;

FIG. 24B is a side view similar to FIG. 24A showing the hub attached tothe catheter;

FIG. 25A is a perspective view of the transducer hub of FIG. 24A;

FIG. 25B is a perspective view of the proximal end of the cathetershowing a connector for the thermocouple wire;

FIG. 26 is a side view of an alternate embodiment of the pressuretransducer hub having a shroud over the elongated member for snapfitting onto the catheter;

FIG. 27 is a schematic view of an alternate embodiment of the pressuretransducer hub extendable into two side ports of the catheter;

FIG. 28A is a perspective view of an alternate embodiment of thetransducer hub and connector;

FIG. 28B is a cutaway side view of the hub and connector showing thepressure transducer prior to connection to the catheter of FIG. 18A, aportion of the hub wall and connector removed to show internalcomponents;

FIG. 28C is a cutaway side view similar to FIG. 28B showing the hubattached to the catheter;

FIG. 28D is a cutaway side view similar to FIG. 28B from the other side;

FIG. 29A is a cutaway side view of the hub and connector of an alternateembodiment showing the pressure transducer prior to connection to thecatheter of FIG. 18A, a portion of the hub wall and connector removed toshow internal components

FIG. 29B is a cutaway view of the hub and connector of FIG. 29A from theother side; and

FIG. 29C is a cutaway view similar to FIG. 29B showing the hub attachedto the catheter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The catheters of the present invention are designed to continuously,safely, and accurately measure maternal uterine contraction pressure(UCP) and are inserted into the urinary bladder through the vaginalcanal. In some embodiments, the catheters can also measure one or moreof maternal core body temperature (CBT), maternal pulse and tissueoxygen saturation (PO2-partial pressure of oxygen), and fetal heart ratethrough the urinary bladder while continuously draining the bladder.These various features are discussed in detail below.

As noted above, the correlation between uterine contraction pressure andurinary bladder pressure directly is known. Gravid uterus is anintra-abdominal organ in direct contact with the urinary bladder. Thatis, the pressure generated by uterine contraction directly exertspressure on the urinary bladder. The catheters of the present inventionutilize this correlation to effectively measure uterine contractionpressure.

Furthermore, in some embodiments, the catheter of the pressure inventionprovides a dual sensor to provide a backup pressure reading. In otherembodiments a dual pressure balloon arrangement is provided. Thesevarious embodiments are discussed in more detail below.

Referring now to the drawings and particular embodiments of the presentinvention wherein like reference numerals identify similar structuralfeatures of the devices disclosed herein, there is illustrated in FIGS.1-5 a catheter of a first embodiment of the present invention. Thecatheter (device) is designated generally by reference numeral 10 and isconfigured for insertion into and positioning within the bladder of thepatient for measuring uterine contraction pressure. The catheter can beconnected to a bedside or central monitor through a wired or blue toothwireless connection to display continuous readings of the maternal andfetal vitals.

The catheter 10 of the present invention can in some embodiments includean alarm or indicator to alert the user if pressure rises beyond athreshold or predetermined value (pressure). The indicator or alarm canbe on the catheter or alternatively on an external device such as themonitor as discussed in more detail below. The alarm can also beconnected via wireless connection to a phone or remote device to alertthe appropriate personnel. The alarm can alternatively or in addition beactivated if a change in pressure measurement exceeds a specified rateover a specified period of time. The alarm can also be triggered byother parameters, e.g., excessive temperature, oxygen levels, fetalheart rate, etc. in embodiments that have sensors for detection of theseparameters.

Turning now to details of the catheter 10, which is also referred toherein as the device 10, and with initial reference to FIGS. 1A, 1B, 3and 4, the three-lumen catheter 10 has an elongated flexible shaft 12having a lumen (channel) 14 extending within the shaft 12 andcommunicating at its distal region with balloon 16 to fluidlycommunicate with balloon 16 to inflate the balloon. Balloon 16 isutilized for monitoring pressure and is also referred to herein as the“pressure balloon.” A fluid port 15 is positioned at a proximal region17 of the catheter 10 for communication with an infusion source forinfusion of gas, e.g., air, through the lumen 14 and into the balloon16. The catheter 10 is shown in FIG. 1A with balloon 16 in the deflatedcondition (position) and in FIG. 1B with the balloon 16 in the inflatedcondition (position). The shaft 12 also includes a second lumen(channel) 20 and third lumen (channel) 24 extending therein (see alsoFIG. 5). In a preferred embodiment, the second lumen 20 is the largestlumen and is configured for continuous drainage of bodily contents fromthe bladder and can be connected to a drainage bag for collection ofurine. Second lumen has a side opening 22 at a distal portion, bestshown in FIG. 3, communicating with the bladder. The third lumen 24terminates at its distal end within balloon 26 to fluidly communicatewith balloon 26 to inflate the balloon 26. The balloon 26 is inflatableto stabilize the catheter 10 to limit movement of the catheter 10 tokeep it in place within the bladder and is also referred to herein as“the stabilizing balloon” or “retention balloon.” A fluid port 28 ispositioned at a proximal region 17 of the catheter 10 for communicationwith an infusion source for infusion of fluid through the lumen 24 andinto the balloon 26. The balloon 26 can be filled with fluid, e.g.,liquid such as water or saline, or a gas, e.g., air. In FIG. 1A, theballoon 26 is shown in the deflated condition and in FIG. 1B in theinflated condition.

Note FIG. 5 is a transverse cross-section of the catheter showing thethree lumens of various shapes. These cross-sectional shapes of thelumens are provided by way of example as one or more of the lumens canbe circular, oval or other symmetrical or asymmetrical shapes intransverse cross section. This also applies to the cross-sectional viewsof the other embodiments herein, e.g., FIGS. 6, 10B and 23, wherein thelumens can be shapes other than those shown. As noted above, preferablythe drainage lumen is the largest lumen but in alternate embodiments oneor more of the other lumens could be larger than the drainage lumen.

A sensor 30 is positioned within lumen 14 adjacent balloon 16. Thewire(s) 32 are shown extending through lumen 14, the sensor 30 andwire(s) 32 being of sufficiently small size so as not to interfere withair flow though lumen 14. The sensor 30 measures pressure of thebladder. The sensor 30 is part of a transducer for converting thevariation in pressure to an electrical signal for transmission to anexternal monitor. The pressure sensor also includes a temperature sensorto measure core temperature of the body as seen inside the bladder.Transmission wire(s) 34 of the temperature sensor extend adjacent wire32 through lumen 14 and terminate external of the catheter 10 forconnection to an external monitor. The transducer can be wired directlyto the monitor or alternatively wired to a converter external of thecatheter for converting the signal received by the transducer andtransmitting a signal to the monitor, e.g., a bedside monitor, todisplay the pressure readings. This is shown schematically in FIG. 2.The readings can be displayed in quantitative form, graphical form orother displays to provide an indicator to the clinician of the bladderpressure. The monitor, or a separate monitor, will display thetemperature readings from sensor 30. Alternatively, thesensor/transducer can be connected to the monitor via a Bluetoothwireless connection.

Wires 32 and 34 can extend though lumen 14 and exit side port 15 forconnection to a converter or monitor or alternatively can be insertedthrough the lumen 14, piercing the wall to enter the lumen 14 distal ofthe side port.

An alarm system can also be provided wherein the system includes acomparator for comparing the measured pressure (and/or temperature) to athreshold (predetermined) value, and if such threshold is exceeded, anindicator, e.g., an alarm, is triggered to indicate to the hospitalpersonnel the excessive pressure and/or temperature. An alarm system canalternatively or in addition be activated if a change in pressuremeasurement exceeds a specified rate over a specified period of time.This would alert the staff to an imminent risk of pressure exceeding acertain value.

The alarm system can be part of the catheter (as shown in FIG. 2) oralternatively external to the catheter 10.

In the embodiments wherein other parameters are measured, the alarmsystem described herein can be tied into measurement of theseparameters. For example, an alarm can be triggered if the fetal heartrate is outside predetermined levels, if oxygen levels are outsidepredetermined levels, if maternal core body temperature is outside corebody levels, etc.

The lumen 14 and space 16 a within balloon 16 together form a closed airchamber, i.e., the lumen 14 forming an air column. With the balloon 16filled with air, pressure on the external wall of the balloon will forcethe balloon to deform inwardly, thereby compressing the air containedwithin the balloon space 16 a and within the lumen 14. The pressuresensor 30 is located in a distal portion of the lumen 14 at the regionof the balloon 16 and thus is positioned at the distal end of the aircolumn. Therefore, the pressure is sensed at the distal region as thesensor 30 detects change in air pressure in lumen 14 due to balloondeformation. Placement of the sensor 30 at a distal location provides apressure reading closer to the source which in some applications canincrease the accuracy by reducing the risk of transmission issues byreducing the amount of interference which could occur due to water, air,clots, tissue, etc. if the transmission is down the air lumen (aircolumn).

Additionally, the pressure measurement occurs about a morecircumferential area of the balloon 16 providing a pressure reading of aregion greater than a point pressure sensor reading. Also, averagepressure over an area of the bladder wall can be computed. Thus, thearea reading gleans information on pressure over more of the bladderwall. Stated another way, the balloon has a relatively large surfacearea with multiple reference points to contribute to average pressurereadings of the surface around it by the sensor.

The air column is charged by insertion of air through the side port 15which communicates with lumen 14. The side port 15 includes a valve toprovide a seal to prevent escape of air from a proximal end. The balloon16 can be composed of impermeable material, or in alternativeembodiments, a permeable or semi-permeable material with an impermeablecoating. This seals the air column at the distal end to prevent escapeof air through the distal end, i.e., through the wall of the balloon 16.Thus, with the lumen sealed at the proximal and distal ends, a closedair system (air charged system) is provided, and without the requirementfor repeated water insertion into the bladder, a fully closed unit isprovided.

In preferred embodiments, when the lumen 14 is air charged, the balloon16 is not fully inflated. This improves the accuracy of the balloon 16transmitting pressure from external the balloon to the interior of theballoon and into the lumen, i.e., air column, by ensuring the balloonhas sufficient compliancy to prevent the balloon from introducingartifact into the pressure reading which would diminish its accuracy.

In some embodiments, the pressure balloon 16 is of a size to receive atleast about 3 cc (3 ml) of fluid. However, other sizes/volumes are alsocontemplated such as about 2 cc or about 1 cc. Additionally, thesevolumes represent the maximum volume of fluid for the balloon, however,as noted above, in preferred embodiments, the pressure balloon 16 is notfully inflated so it would receive less than the maximum volume. Thus,with a balloon of X volume, the fluid would receive X-Y fluid, with Yrepresenting the amount of desired extra space to achieved desiredcompliancy of the balloon while still enable sufficient inflation of theballoon to achieve its pressure induced deformation function.

Note in this embodiment, the stabilizing balloon 26, also referred to asthe proximal retention balloon, is positioned proximal of the pressureballoon 16. Also, in this embodiment, the stabilizing balloon 26 islarger than the pressure balloon 16. By way of example, the stabilizingballoon 26 can have a fully expanded diameter of about 23 mm and thepressure balloon 16 can have a fully expanded diameter of about 15 mm,although other dimensions or diameters for these balloons are alsocontemplated. By way of example, the stabilizing balloon 26 can have acapacity of about 10 cc (10 ml) of air, although other sizes/volumes arealso contemplated. Note these sizes/volumes for both balloons areprovided by way of example and other sizes are also contemplated.Alternatively, the stabilizing balloon can be the same size or smallerthan the pressure balloon. Various shapes of the balloons are alsocontemplated.

Additionally, although the balloon 26 is positioned proximal of theballoon 16, it is also contemplated that the balloon 26 be positioneddistal of balloon 16. The axial spacing of the balloons 16, 26 enablethe stabilizing balloon 26 to engage the bladder wall to provide asufficient radial force thereon for securing/mounting the catheterwithin the bladder without interfering with the function of balloon 16.

It should be appreciated that although the stabilizing balloon is shownin the embodiment of FIG. 1, it is also contemplated as an alternative,the catheter and system of FIGS. 1 and 2 can be utilized without thestabilizing balloon 26 as shown for example in FIG. 7. Similarly,although the various embodiments (catheters) disclosed herein utilize astabilizing balloon, it is also contemplated that alternatively thecatheter of these various embodiments not include a stabilizing balloon.In the embodiment of FIG. 7, catheter 50 has two lumens: 1) a lumen forcontinuous drainage of the bladder which has a side opening at a distalend to communicate with the bladder (similar to lumen 20 of FIG. 1); and2) an air lumen filling pressure balloon 16 via insertion of air throughside port 55. The sensor 30 is positioned within the air lumen in thesame manner as sensor 30 is in lumen 14 or in the alternative positionsdisclosed herein. Thus, the pressure and temperature sensing describedin conjunction with FIG. 1A is fully applicable to the embodiment ofFIG. 7. Besides the elimination of the stabilizing balloon and its lumenand side port, catheter 50 is the same as catheter 10,

Note that although only one sensor is shown in FIG. 3, it is alsocontemplated that multiple sensors can be provided. Also, note that thesensor 30 is positioned in lumen 14 at a mid-portion of the balloon,i.e., just proximal where the opening in lumen 14 communicates with theinterior 16 a of the balloon 16. It is also contemplated that the sensorcan be placed at another portion within the lumen 14, e.g., a moreproximal portion, with respect to the lumen opening. Also, the lumenopening need not be at the mid portion of the balloon and can be atother regions of the balloon to communicate with the interior space 16a. Note if multiple sensors are provided, they can be positioned atvarious locations within the lumen 14.

As shown, the sensor 30 and its transmission wires are located in thesame lumen 14 also used for initial inflation gas, e.g., air, forballoon 16 and for the air charged column. This minimizes the overalltransverse cross-section (e.g., diameter) of the catheter 10 byminimizing the number of lumens since additional lumens requireadditional wall space of the catheter. However, it is also contemplatedin alternate embodiments that the sensor is in a dedicated lumenseparate from the inflation lumen 14. This can be useful if a largersensor or additional wires are utilized which would restrict the airlumen if provided therein. This is also useful if a specific sized lumenfor the sensor and wires is desired to be different than the sized lumenfor the air column. Provision of a separate lumen is shown in thecross-sectional view of FIG. 6 wherein in this alternate embodimentcatheter 40 has four lumens: 1) lumen 42 for drainage of the bladderwhich has a side opening at a distal end to communicate with the bladder(similar to lumen 20 of FIG. 1); 2) lumen 44 for filling pressureballoon 16; 3) lumen 46 for filling stabilizing balloon 26; and 4) lumen50 in which sensor 30 and its transmission wires 32 and temperaturesensor wires 34 are contained. In all other respects, catheter 40 isidentical to catheter 10 and its balloons, air channel, sensor, etc.would perform the same function as catheter 10. Therefore, for brevity,further details of catheter 40 are not discussed herein as thediscussion of catheter 10 and its components and function are fullyapplicable to the catheter 40 of the embodiment of FIG. 6.

Turning now to the use of the catheter 10, the catheter 10 is insertedinto the bladder. Note catheter 50 (and catheter 40) would be used inthe same manner. The balloon 26 is inflated to secure the catheter 10 inplace during the procedure by insertion of a fluid (liquid or gas)through side port 28 which is in fluid communication with lumen 24. Thesystem is charged by inflation of the balloon 16, i.e., preferablypartial inflation for the reasons discussed above, by insertion of airvia a syringe or other inflation device through port 15 which is influid communication with lumen 14. As discussed above, the catheter 10is a closed system with the pressure balloon 16 sealed so that airinserted through lumen 14 and into balloon 16 cannot escape throughballoon 16. Thus, a closed chamber is formed comprising the internalspace 16 a of the balloon 16 and the internal lumen 14 communicatingwith the internal space 16 a of balloon 16. With the balloon 16inflated, pressure monitoring can commence. When external pressure isapplied to an outer surface 16 b of the balloon 16, caused by outwarduterine pressure which applies pressure to the bladder wall and thusagainst the wall of balloon 16, the gas within the chamber iscompressed. The sensor 30 at the distal end of lumen 14 providescontinuous pressure readings, converted to an electrical signal by thetransducer within the distal end of lumen 14, and then electricallycommunicates through wire(s) 32 extending through lumen 14, exitingthrough the proximal side port 15 and connected to an external monitor44. Note the wire can terminate at the proximal end in a plug inconnector which can be connected directly to the monitor oralternatively plugged into a converter to convert the signals from thetransducer in the embodiments wherein the converter is interposedbetween the wires and monitor (see e.g., the system of FIG. 2) toprovide the aforedescribed graphic display. Although, the system iscapable of continuous pressure and temperature monitoring, it can alsobe adapted if desired for periodic monitoring so the pressure and/ortemperature readings can be taken at intervals or on demand by theclinician.

In the embodiments wherein an indicator is provided, if the measuredpressure exceeds a threshold value, and/or a change in pressuremeasurement exceeds a specific rate over a specific time period, theindicator would alert the clinician, e.g., via a visual indication or anaudible indication, that the threshold is exceeded. The indicator insome embodiments can include an audible or visual alarm (shownschematically in FIG. 2). In the embodiments having an indicator, theindicator can be provided on a proximal end of the catheter whichextends out of the patient or the indicator can be part of an externalcomponent such as the monitor or a separate alarm system. A visual,audible, or other indicator can likewise be provided in any of the otherembodiments disclosed herein to indicate if the measured pressure,measured temperature or any other measured parameter exceeds apredetermined value, and such indicator can include an alarm and can bepart of the catheter or a separate component.

The catheter 10 can be positioned in close proximity to the fetus andthus can include one or more pressure sensors in an additional channel(lumen) of the catheter to detect fetal heart rate. The catheter canalso include a channel (lumen) with one or more sensors to detectcontinuous maternal PO2. Such additional sensor(s) can be provided inany of the catheters disclosed herein. Thus, in some embodiments, thecatheter 10 (as well as the other catheters disclosed herein) canmeasure intrauterine pressure along with measurement or detection,either continuously or intermittently, of one or more of thefollowing; 1) maternal core body temperature; 2) maternal respiration;3) maternal PO2; and 4) fetal heart rate. This is in addition tocontinuous drainage of bodily contents from the bladder. One way forexample to measure fetal heart rate is to place a micro air chargedchamber in the retention balloon to help detect fetal heart rate.Sensors can be provided to detect continuous maternal PO2 located nearthe urethra, proximal to the stabilizing balloon.

In the embodiment of FIGS. 1-7, within the distal end of the air lumen14 is a pressure transducer and pressure sensor 30 which also includes atemperature sensor. In the alternate embodiment of FIGS. 8A-10B, thetemperature sensor is separate from the pressure sensor. Morespecifically, catheter 60 has an elongated flexible shaft 62 having alumen (channel) 64 extending within the shaft 62 and fluidlycommunicating at a distal region with balloon 66 to inflate the balloon.Balloon 66 (also referred to as the pressure balloon) is utilized formonitoring pressure. A fluid side port 65 is positioned at a proximalregion 67 of the catheter 60 for communication with an infusion sourcefor infusion of gas e.g., air, through the lumen 64 and into the balloon66. The catheter 60 is shown in FIG. 8A with balloon 66 in the deflatedcondition (position) and in FIG. 9 with the balloon 66 in the inflatedcondition (position). The shaft 62 also includes a second lumen(channel) 70 and third lumen (channel) 74 extending therein. The secondlumen 70 is preferably the largest lumen and is configured for drainageof the bladder. Second lumen 70 has a side opening 72 at a distalportion communicating with the bladder. The third lumen 74 communicatesat a distal region with stabilizing (retention) balloon 76 to fluidlycommunicate with balloon 76 to inflate the balloon. The stabilizingballoon 76 is inflatable to stabilize the catheter 60 to limit movementof the catheter 60 to keep it in place within the bladder. A side fluidport 75 is positioned at a proximal region 67 of the catheter 60 forcommunication with an infusion source for infusion of fluid through thelumen 74 and into the balloon 76.

Sensor 80 is positioned in lumen 64 for sensing pressure in response toballoon deformation in the same manner as sensor 30. Sensor 82 ispositioned in lumen 64 distal of sensor 80 for measuring maternal corebody temperature. Temperature sensor 82 can be a thermocouple, athermistor or other types of temperature sensors. As shown in FIG. 9,the temperature sensor is distal of the balloon 66 and its transmissionwire(s) 83 extend proximally within lumen 64, exiting a proximal end forcommunication with a monitor or alternatively a converter whichcommunicates with the monitor. Wire(s) 81 of sensor 80 also extendthrough lumen 64, alongside wire(s) 83, exiting through the side port 65or a proximal end wall or a side wall of the lumen. It is alsocontemplated that alternatively one or both of sensors 80 and 82, andtheir associated wires 81, 83, can be positioned in a separate “fourth”lumen such as in the embodiment of FIG. 6 so that the “inflation lumen”and the “sensor lumen” are independent.

In use, catheter 60 is inserted into the bladder and stabilizing balloon76 is inflated to secure the catheter 60 in place. The system is chargedby inflation of the balloon 66, i.e., preferably partially inflated forthe reasons discussed above, by insertion of air (or other gas) throughport 65 which is in fluid communication with lumen 64 in a closed systemformed by the internal space 66 a of the balloon 66 and the internallumen 64 communicating with the internal space 66 a of balloon 66. Withthe balloon 66 inflated, pressure monitoring can commence as externalpressure applied to an outer surface of the balloon 66 compresses thegas within the chamber. The sensor 80 at the distal end of lumen 64provides continuous pressure readings, converted to an electrical signalby the transducer within the distal end of lumen, and then electricallycommunicates through wires 82 extending through lumen 64 to an externalmonitor either directly or via a converter. The sensor 82 at the distalend of lumen 64 provides continuous temperature readings via wires 83communicating directly or indirectly with the monitor, Although, thesystem is capable of continuous pressure and continuous temperaturemonitoring, it can also be adapted if desired for periodic monitoring sothe pressure and/or temperature readings can be taken at intervals or ondemand by the clinician. If provided, measurements of other parametersdiscussed above and in the various embodiments disclosure herein canalso be taken continuously or at intervals.

In the alternate embodiment of FIG. 11, catheter 90 is identical to thecatheter 60 of FIG. 8 except that the pressure transducer is positionedexternal of the catheter rather than in the air (or other gas) lumen.That is, instead of the pressure transducer including the sensor beingpositioned within the distal end of the air lumen, the pressure sensor92 is positioned within lumen 94 at the distal end of the lumen andtransmission wire(s) 93 connect the sensor 92 to the pressure transducer96 positioned outside of the patient at a proximal region of catheter90. As shown, the pressure transducer 90 can be positioned in a sideport of catheter 90. In alternate embodiments, it is positioned outsidethe catheter. The temperature sensor 95 is positioned within lumen 94along with transmission wire (97) in the same manner as temperature 82and wires 83 are positioned in catheter 60 described above. Thetemperature sensor can be a separate sensor positioned distal of thepressure sensor 92 as shown or alternatively it can be part of sensor 92as in the embodiment of FIG. 1. In all other respects, catheter 90 isidentical to catheter 60 and therefore for brevity further discussion isnot provided since the structure and function of the balloons, thelumens, the positioning of the sensors in the lumens, the continuouspressure monitoring, etc., as well as the aforedescribed alternativearrangements of catheter 60, are fully applicable to the catheter 90.

In the alternate embodiment of FIG. 12, catheter 100 is identical tocatheter 60 of FIG. 8 except that both the pressure transducer and thepressure sensor are positioned external of the patient at a proximalregion of the catheter rather than in the air lumen. That is, instead ofthe pressure transducer and sensor being positioned within and at thedistal end of the air lumen, the transducer and pressure sensor 102 arepositioned in a side port 103 of the catheter 100. In alternativeembodiments, they are positioned outside the catheter. In yet otherembodiments, the pressure sensor and/or pressure transducer can bepositioned within the air (or other gas) lumen at a proximal end of theair lumen. The temperature sensor 107 is positioned within lumen 104along with transmission wire(s) 108 in the same manner as temperaturesensor 82 and wire 83 are positioned in catheter 60 described above. Thesystem is charged by inflation of the balloon 106, i.e., preferablypartially inflated for the reasons discussed above, by insertion of airvia a syringe or other injection method through the side port 103 whichis in fluid communication with lumen 104. The catheter 100 is a closedsystem with the balloon 106 sealed so that air inserted through lumen104 and into balloon 106 cannot escape through balloon 106. Thus, aclosed chamber is formed comprising the internal space of the balloon106 and the internal lumen 104 communicating with the internal space ofballoon 106. With the balloon 106 inflated, pressure monitoring cancommence. When external pressure is applied to an outer surface of theballoon 106, caused by outward uterine contraction pressure whichapplies pressure to the bladder wall and thus against the wall ofballoon 16, the air within the chamber of the balloon 106 is compressed.This compresses the air within the lumen 104 creating an air chargedcolumn along the lumen 104. The sensor 102 at the proximal end ofcatheter 100 measures pressure of the air column and its proximal endand can provide continuous pressure readings, converted to an electricalsignal by the transducer at the proximal end or external of the catheter100, and then electrically communicates through wire(s) 103 to anexternal monitor. The balloon 106, like balloon 16, balloon 66 and theother pressure balloons described herein, is of sufficiently large sizeto provide a sufficient circumferential area for detection of pressurechanges along several parts of the bladder wall, thereby providing anaverage pressure and enabling more accurate pressure readings. Balloon109 is a stabilizing balloon like balloon 76 inflated through a separatelumen.

Note the wires of the sensor 102 can terminate at the proximal end in aplug in connector which can be connected directly to the monitor oralternatively plugged into a converter to convert the signals from thetransducer in the embodiments wherein the converter is interposedbetween the wires and monitor (see e.g. the system of FIG. 2) to providethe aforedescribed graphic display. Although, the system is capable ofcontinuous pressure and temperature monitoring, it can also be adaptedif desired for periodic monitoring so the pressure and/or temperaturereadings can be taken at intervals or on demand by the clinician. In allother respects, catheter 100 is identical to catheter 60 and thereforefor brevity further discussion is not provided since the structure andfunction of the balloons, the continuous pressure monitoring, etc., aswell as the aforedescribed alternative arrangements of catheter 60, arefully applicable to the catheter 100.

FIGS. 13A and 13B illustrate an alternate embodiment wherein catheter110 includes a pressure sensor within the balloon. More specifically,catheter 110 has an elongated flexible shaft 112 having a lumen(channel) 114 extending within the shaft 112 and communicating at itsdistal region with balloon 116 to fluidly communicate with balloon 116to inflate the balloon. Balloon 116 (also referred to as the pressureballoon) is utilized for monitoring pressure. A fluid side port 115 ispositioned at a proximal region 117 of the catheter 110 forcommunication with an infusion source for infusion of gas through thelumen 114 and into the balloon 116. The shaft 112 also includes a secondlumen (channel) 120 and third lumen (channel) 122 extending therein.Second lumen 122 has a side opening 124 at a distal portioncommunicating with the bladder for drainage. The third lumen 122communicates at a distal region with stabilizing balloon 126 to fluidlycommunicate with balloon 126 to inflate the balloon to limit movement ofthe catheter 110 to keep it in place within the bladder. A fluid port113 is positioned at a proximal region 117 of the catheter 110 forcommunication with an infusion source for infusion of fluid through thelumen 122 and into the balloon 126.

The pressure sensor 130 is carried by catheter 110 and positioned withinthe balloon 116 to measure pressure in response to deformation of theballoon 116 in response to pressure exerted on an outer wall of balloon116 due to uterine contraction pressure. The pressure transducer caninclude the sensor 130 or can be a separate component positioned at aproximal end of the catheter external of the catheter 110. Thetemperature sensor 132 can be positioned within the balloon 116, part ofsensor 130, or alternatively positioned within lumen 114 (as shown inFIG. 13B), with its transmission wire(s) 127 extending within the gas,e.g., air, lumen 114 along with the wires of sensor 130 in the samemanner as in catheter 60 described above.

In all other respects, catheter 110 is identical to catheter 60 andtherefore for brevity further discussion is not provided since thestructure and function of the balloons, lumens, continuous pressuremonitoring, etc. as well as the aforedescribed alternative arrangementsof catheter 60, are fully applicable to the catheter 110.

As discussed above, the pressure balloon has a large circumferentialarea (and large volume) to provide multiple reference points forpressure readings and to provide an average pressure to enable moreaccurate readings. Thus, the pressure balloon provides for grossmeasurement. In an alternate embodiment shown in FIG. 15, the pressureballoon for detecting pressure, designated by reference numeral 142,forms an outer balloon of catheter 140. Contained within the outerballoon 142 is an inner balloon 143. The inner balloon 143 provides asmaller diameter balloon and a smaller circumference (and volume) thanthe outer balloon 142. The inner balloon 143 together with the lumen 144forms a smaller air (or other gas) column than in the embodimentsdiscussed above where the larger balloon internal space communicatesdirectly with the air lumen. This provides finer measurements. Thus, thecompliant outer balloon 142 compresses the compliant inner balloon 143which compresses the air within air lumen 144. The closed system isthereby formed by the internal space of the inner balloon 143 and thelumen 144. In certain instances, the smaller balloon air column canprovide a more accurate reading from the average pressure determined bythe larger outer balloon 142.

The inner balloon 143 and outer balloon 142 can beseparately/independently inflated and closed with respect to each otherso there is no communication, e.g. passage of gas or liquid, between theinner and outer balloons 143, 142.

The proximal and distal end of the inner balloon 143 in the illustratedembodiment are within the confines of the outer balloon 142, i.e., theproximal end of the inner balloon 143 is distal of the proximal end ofthe outer balloon 142 and the distal end of the inner balloon 143 isproximal of the distal end of the outer balloon 142. Thus the innerballoon 143 is fully encapsulated within the outer balloon 142.

With this inner/outer balloon arrangement, the larger outer surface ofthe outer balloon 143 takes gross measurements and then the forces areconcentrated on the smaller inner balloon to amplify/concentratepressure on the small area of the inner balloon so small changes can bedetected and waves transmitted to the pressure transducer (via thelength of the lumen) to a proximal transducer, e.g. an externalpressure.

The pressure transducer and pressure sensor 150 can be positioned withinthe lumen 144 in the same manner as sensor 30 of FIG. 1 and can functionin the same manner. Alternatively, the pressure transducer can be at aproximal end of the catheter 140 as in the embodiment of FIG. 12 orexternal of the catheter. A temperature sensor can be part of sensor 150as in the embodiment of FIG. 1 or alternatively a separate componentwhich can be positioned for example distal of the pressure sensor withinthe air lumen as in the embodiment of FIG. 8. The transmission wires ofthe pressure sensor 150 and the temperature sensor extend through lumen144.

The catheter 140 can optionally include a stabilizing (retention)balloon 145 similar to balloon 76 of FIG. 8. The catheter 140 would havea lumen, e.g., lumen 146, to inflate the stabilizing balloon 145. Lumen148 with side opening 149 provides for drainage of the bladder. Lumen144 which is used to inflate the inner balloon 143 and create the gascolumn has an opening at a distal region to communicate with innerballoon 143. A separate lumen 147 has an opening at a distal region tocommunicate with the outer balloon 142 to fill the outer balloon 142.

In use, catheter 140 is inserted into the bladder and stabilizingballoon 145 is inflated to secure the catheter 140 in place. The systemis charged by inflation of the inner balloon 143, preferably partiallyinflated for the reasons discussed above, by insertion of air through aside port which is in fluid communication with lumen 144 in a closedsystem formed by the internal space 143 a of the inner balloon 143 andthe internal lumen 144 communicating with the internal space 143 a ofinner balloon 143. Outer balloon 142 is filled, preferably partiallyinflated for the reasons discussed above, via injection of air through aseparate lumen. With the outer balloon 142 inflated, pressure monitoringcan commence as external pressure applied to the larger circumferentialouter surface of the outer balloon 142 compresses and deforms the outerballoon 142 which compresses the inner balloon 143. As the inner balloon143 is compressed and deformed in response to compression/deformation ofthe outer balloon 142 based on changes to bladder pressure, the sensor150 at the distal end of lumen 144 provides continuous pressurereadings, converted to an electrical signal by the transducer within thedistal end of lumen 144, and then electrically communicates throughwires 152 extending through lumen 144 to an external monitor eitherdirectly or via a converter. Although, the system is capable ofcontinuous pressure and continuous temperature monitoring as in theother embodiments disclosed herein, it can also be adapted if desiredfor periodic monitoring so the pressure and/or temperature readings canbe taken at intervals or on demand by the clinician.

Note that although separate lumens are provided for the inflation ofinner balloon 143 and outer balloon 142, in an alternate embodiment, asingle lumen can be utilized to inflate both balloons 143 and 142.

FIG. 16 illustrates an alternate embodiment of catheter 140, designatedby reference numeral 140′. Catheter 140′ is identical to catheter 140except a larger outer balloon 142′ is provided to cover more surfacearea for pressure readings. In all other respects, catheter 140′ isidentical to catheter 140 and for brevity further discussion is notprovided since the features and functions of catheter 140, and itsalternatives such as single or two lumens for inner and outer ballooninflation, are fully applicable to catheter 140′. For ease ofunderstanding, the components of catheter 140′ which are identical tocatheter 140 are given the same reference numerals as catheter 140.

Note that the larger balloon 142′ can be used with the catheters of anyof the embodiments described herein. Thus, a pressure balloon of thelarger size balloon 142′ can be used instead of the smaller pressureballoons illustrated in the drawings. Note the size of the balloons isprovided by way of example and are not necessarily drawn to scalecomparatively to the other components.

FIG. 17 illustrates an alternate embodiment of catheter 140, designatedby reference numeral 140″. Catheter 140″ is identical to catheter 140except a pear shaped larger outer balloon 142″ is provided. The largerballoon covers more surface area for pressure readings. The pear shapecould in certain applications decrease the risk of obstruction andprovide more tactile continuity of the balloon to the bladder wallgiving a better transmission of uterine contraction pressure to theinternal sensor. In all other respects, catheter 140″ is identical tocatheter 140 and for brevity further discussion is not provided sincethe features and functions of catheter 140, and its alternatives such assingle or two lumens for inner and outer balloon inflation, are fullyapplicable to catheter 140″. For ease of understanding, the componentsof catheter 140″ which are identical to catheter 140 are given the samereference numerals as catheter 140.

FIG. 17B illustrates a catheter identical to catheter 140″ withidentical balloons, the only difference being that the side opening 149′is positioned proximal of the balloon 143 rather than distal of theballoon as in FIG. 17A. That is, opening 149′, in communication with thecatheter lumen 148′ for drainage of the bladder, is positioned betweenthe stabilizing balloon 145 and the inner and outer pressure (and inner)pressure balloon 142″ (and 143). Thus, it is distal of the stabilizingballoon 145 and proximal of the outer balloon 142″.

Note that the positioning of the side opening for drainage of FIG. 17B,which communicates with the drainage lumen of the catheter, can beutilized with any of the catheters disclosed herein. Thus, in thecatheters disclosed in the various embodiments herein, instead of thedrainage opening positioned distal of the pressure balloon(s), it can beproximal of the pressure balloon and distal of the stabilizing balloonso it is between the two balloons.

Note that the pear shaped balloon 142″ can be used with the catheters ofany of the embodiments described herein. Thus, a pressure balloon of thepear shape of balloon 142″, and of larger size if desirable, can be usedinstead of the pressure balloons illustrated in the drawings.

FIGS. 18-25B illustrate an alternate embodiment of the catheter of thepresent invention. The pressure balloon for detecting pressure,designated by reference numeral 202, forms an outer balloon of catheter200. Contained within the outer balloon 202 is an inner balloon 204. Theinner balloon 204 provides a smaller diameter balloon and a smallercircumference (and volume) than the outer balloon 202. The inner balloon204 together with the lumen 214, which communicates with the innerballoon 204 for inflation thereof, forms a smaller air column as in theembodiments of FIGS. 15-17. This provides finer measurements. Thus, thecompliant outer balloon 202 compresses the outer wall 205 of thecompliant inner balloon 204 which compresses the air (or other gas)within air lumen 214. The closed system is thereby formed by theinternal space 204 a of the inner balloon 204 and the lumen 214. Thesmaller balloon air column can in certain instances provide a moreaccurate reading from the average pressure determined by the largerouter balloon 202.

The pressure transducer and pressure sensor are external to catheter 200and mounted to port 218 at the proximal end 201 of catheter 200. Morespecifically, a transducer hub or housing, designated generally byreference numeral 240, contains the pressure transducer and sensor andis mounted to the angled side port 218. In the embodiment of FIG. 18A,the hub 240 is mounted over the port 218 and can be locked or securedthereto such as by a friction fit, snap fit, threaded attachment, alatch, etc., maintaining an airtight seal so the air is contained withinthe lumen 214 and balloon 204. The hub 240 has an elongated (rod-like)member or nose 242 extending distally therefrom (FIG. 24A) dimensionedto be inserted through the proximal opening in port 218 and into airlumen 214. (Note the air lumen 214 as the other lumens extend into theirrespective angled side ports). The elongated member 242 also has achannel 244 extending therethrough to allow the pressure wave to travelthrough to the pressure sensor. Although in preferred embodiments noadditional air needs to be injected into inner balloon 204 via lumen 214after attachment of hub 240, it is also contemplated that a port oropening can be provided in hub 240 to receive an injection device forinjection of additional air. Such additional air can communicate withand flow through channel 244 of elongated member 242, into lumen 214 andinto inner balloon 204 for inflation, or alternatively, a side port oropening in angled port downstream of the elongated member 242 could beprovided.

To charge the system, when the hub 240 is mounted to the side port 218,the elongated member 242 extends into lumen 214 to advance air throughthe air lumen 214 into inner balloon 204 to expand inner balloon 204. Insome embodiments, 0.2 cc of air can be displaced/advanced by the member242, although other volumes are also contemplated. Thus, as can beappreciated, mounting of the hub 240 to the catheter 200 automaticallypressurizes the air lumen/chamber and expands the inner balloon 204.Note the inner balloon 204 can be partially or fully inflated(expanded), dependent on the amount of air advanced into the innerballoon 204. Further note that the lumen 214 is not vented to atmospherewhen the transducer hub 240 is attached and air is advanced through theair lumen. The port 218 can include a closable seal through which theelongated member 242 is inserted but maintains the seal when theelongated member 242 remains in the lumen 214.

Lumen 214 which is used to inflate the inner balloon 204 and create theair column has an opening at a distal region to communicate with theinterior of inner balloon 204. Lumen 212 of catheter has an opening at adistal region to communicate with the outer balloon 202 to fill theouter balloon 202. Angled port (extension) 222 at the proximal end ofcatheter 200 receives an inflation device to inflate, either fully orpartially, the outer balloon 202.

Note as in the other embodiments disclosed herein, air is described asthe preferred gas for creating the column and expanding the balloon,however, other gasses are also contemplated for each of the embodimentsherein.

The outer balloon 202 can be shaped such that a distal region 207 a(FIGS. 20A-20C) has an outer transverse cross-sectional dimension, e.g.,diameter, greater than an outer transverse cross-sectional dimension,e.g., diameter, of the proximal region 207 b. A smooth transition(taper) can be provided between the distal region 207 a and proximalregion 207 b. Note the balloon 202 can be pear shaped as shown in FIGS.20B and 20C although other configurations are also contemplated. Thispear shape in some applications is designed to conform to the shape ofthe bladder.

The inner and outer balloons 204, 202 can by way of example be made ofurethane, although other materials are also contemplated.

A temperature sensor 230, such as a thermocouple, is positioned withinthe catheter 200 at a distal end to measure maternal core bodytemperature. The sensor 230 is shown positioned in a lumen 216 separatefrom the lumens 214 and 212. One or more wires 232 extend from thesensor 230 through the lumen 216, exiting the lumen 216 and catheter 200at a proximal end 216 a between the angled extensions/ports of thecatheter 200, e.g., between the port 218 for the inner balloon 204 andthe port 222 for the outer balloon 202. A connector 234, e.g., a maleconnector, is at the proximal terminal end of the wire 232 as shown inFIG. 25B. The transducer hub 240 includes a connector 247 with openings249 (FIG. 25A) which receive the connector 234 of the wire 232. When thehub 240 is mounted to port 218 of catheter 200, the connector 234 of thewire is automatically connected to a connector carried by or within thehub 240 which is in communication with a temperature monitor. Note theconnector, e.g., female connector, within or carried by the hub 240 canalready be mounted to an external temperature monitor via a cable whenthe hub 240 is mounted to catheter 218 or alternatively the hub 240 canfirst be mounted to port 218 of the catheter 200 and then a cable isconnected between the temperature monitor and catheter 200. In theillustrated embodiment of FIG. 25A, the wire connector 234 can plug intothe openings of connector 247 positioned on the hub 240. Note theconnector 247 can also be internal of the hub with an opening in thewall of the hub to enable access for the wire connector. Also note thatalternatively the wire can include a female connector and the hub canhave a male connector. Other types of connectors/connections are alsocontemplated.

As can be appreciated, connection of the transducer hub 240 to thecatheter 200 (port 218) a) automatically connects the temperature sensor230 to a connector for communication with a temperature monitor cable;and b) automatically advances air through the first lumen 214 to expandthe inner balloon 204.

The catheter 200 can optionally include a stabilizing (retention)balloon 206 similar to balloon 76 of FIG. 8A. The stabilizing balloon206 can be made of silicone, although other materials are alsocontemplated. If provided, the catheter 200 would have a lumen, e.g.,lumen 208, to inflate the stabilizing balloon 206. Angled side port 217can be provided in communication with lumen 208 for injection of aliquid or gas to expand the stabilizing balloon 206. The foregoingdescription of the stabilizing balloons is fully applicable to balloon206. Catheter 200 also includes a lumen 211 with a distal side opening211 a (FIG. 18B) to provide for drainage of the bladder as in theaforedescribed embodiments. In the illustrated embodiment, the sideopening 211 a is distal of outer balloon 202 and inner balloon 204 anddistal of the stabilizing balloon 210 which as shown is proximal ofouter balloon 202 and inner balloon 204. In alternate embodiments, thestabilizing balloon 206 can be distal of the outer balloon 202.

Thus, in the embodiment of FIG. 18A, catheter 200 has five lumens: 1)lumen 214 communicating with inner balloon 204 to inflate the innerballoon 204 and forming the air filled chamber; 2) lumen 212communicating with outer balloon 202 for inflating outer balloon 202; 3)lumen 210 communicating with the stabilizing balloon 206 to inflatestabilizing balloon 206; 4) drainage lumen 211 having a side opening 211a at a distal end for drainage of the bladder; and 5) lumen 216 for thetemperature sensor and sensor wire(s) 232. Catheter 200 also has threeangled extensions/ports at its proximal end 201: 1) port 218 for accessto lumen 214 to inflate the inner balloon 204; 2) port 222 for access tolumen 212 to inflate outer balloon 202; and 3) port 217 for access tolumen 210 to inflate stabilizing balloon 206. Drainage lumen 211 extendslinearly terminating in opening 223. Lumen 216 terminates proximally atthe region of the angled ports 218, 222 through which wire 232 can exitfrom the catheter 200 for connection to a temperature monitor via hub240. Note the location of the ports can vary from that illustrated inFIG. 18. Also, the cross-sectional dimension and size of the lumens canvary from that shown in FIG. 23 as FIG. 23 provides just one example ofthe size, e.g., diameter, of the lumen as well as one example of theshape/cross-sectional configuration and location. The catheter 200, asin the foregoing embodiments, can have an atraumatic tip 209.

In use, catheter 200 is inserted into the bladder and stabilizingballoon 206 is inflated to secure the catheter 200 in place. The systemis charged by inflation of the inner balloon 204, preferably partiallyinflated for the reasons discussed above, by advancement of air throughlumen 214 upon attachment of the pressure transducer 240 to the port 218of catheter 200. Such attachment moves elongated member 242 into lumen214 to displace the air (or other gas) already in the lumen 214 toexpand the inner balloon 204. A closed system is formed by the internalspace 204 a of the inner balloon 204 and the internal lumen 214communicating with the internal space 204 a of inner balloon 204. In apreferred embodiment, additional air does not need to be added to theballoon 204/lumen 214. Outer balloon 202 is filled, preferably partiallyinflated for the reasons discussed above, via injection of air throughthe separate port 219 which communicates with lumen 212 of catheter 200.With the outer balloon 202 inflated, pressure monitoring can commence asexternal pressure applied to the larger circumferential outer surface ofthe outer balloon 202 compresses and deforms the outer balloon 202 whichexerts a force on outer wall 205 of inner balloon 204 and compresses theinner balloon 204. As the inner balloon 204 is compressed and deformedin response to compression/deformation of the outer balloon 202 based onchanges to bladder pressure (as a result of uterine contractionpressure), the pressure sensor within the external hub 240 attached atthe proximal end of the catheter 200 provides continuous pressurereadings, converted to an electrical signal by the transducer within thehub 240, and then electrically communicates through a connector, e.g.cable 245, to an external monitor either directly or via a converter todisplay pressure readings. Although, the system is capable of continuouspressure and continuous temperature monitoring, it can also be adaptedif desired for periodic monitoring so the pressure and/or temperaturereadings can be taken at intervals or on demand by the clinician.Temperature readings are also taken during the procedure as temperaturesensor 230 is connected to a temperature monitor via wire 232 connectedto a connector of hub 240 which is connected to the temperature monitor,either directly or indirectly via a converter, to display temperatures.The temperature monitor can be separate from the pressure displaymonitor or alternatively integrated into one monitor. Cable 245 canconnect to the temperature monitor as well (directly or via a converter)or a separate cable extending from the hub 240 could be provided forconnection to the temperature monitor.

Note that although separate lumens are provided for the inflation ofinner balloon 202 and outer balloon 204, in an alternate embodiment, asingle lumen can be utilized to inflate both balloons 202 and 204. Insuch embodiment, catheter 200 can have one less angled port and one lesslumen since inflation of the outer balloon 202 would be through port 218and lumen 214.

As noted above, preferably no additional air needs to be added aftermounting of hub 240. However, it is also contemplated that in alternateembodiments a port can be provided in communication with hub 240 toenable subsequent injection of air though lumen 214 and into innerballoon 204. Additionally, outer balloon 202 can in some embodimentsreceive additional fluid injection via port 222 during the procedure.

FIG. 26 illustrates an alternate embodiment of the pressure transducerhub. In this embodiment, hub 250 has a shroud 254 (shown schematically)positioned over elongated member 252. This helps protect/shield theelongated member 252. When the transducer 240 is mounted to the port 260of the catheter, the shroud 254 fits over cover 260 of port 218 and isretained by a snap fit or by other methods of securement.

In the aforedescribed embodiment, mounting of the transducer hub a)automatically connects the temperature sensor to a connector forcommunication with a temperature monitor cable; and b) automaticallyadvances air through the first lumen to expand the inner balloon. In theembodiment of FIG. 27, the pressure transducer hub 270 has a secondelongated member 274 extending therefrom. When transducer hub 270 ismounted to the catheter, e.g., port 218, elongated member 272 enters theair lumen in the same manner as elongated member 242 of FIG. 24B.Additionally, elongated member 274 automatically enters the lumen 210 atport 222 which communicates with the outer balloon 202. Therefore, inthis embodiment, mounting of the transducer hub 270 a) automaticallyconnects the temperature sensor to a connector for communication withtemperature monitor cable as in the embodiment of FIG. 18-25B; b)automatically advances air through the first lumen to expand the innerballoon as in the embodiment of FIG. 18-25B; and c) automaticallyadvances air through lumen 210 communicating with the outer balloon 202to inflate (expand) the outer balloon 202. The catheter of FIG. 27 (andFIG. 26) is otherwise identical to catheter 200 of FIG. 18 so forbrevity further discussion is not provided since the description of thefunction and elements of catheter 200 are fully applicable to thecatheter of FIG. 27 (and to the catheter of FIG. 26).

FIGS. 28A-28D show an alternate embodiment of the hub/connector. Thepressure transducer is external to catheter 280 and mounted to port 282at the proximal end 281 of catheter 280 via connector (housing) 290.Catheter 280 is identical to catheter 200 of FIG. 18A except for theconnector and transducer hub.

More specifically, a transducer hub or housing, designated generally byreference numeral 300, contains the pressure transducer and sensor 309and is mounted to the angled side port 282. In the embodiment of FIG.28A, the hub 300 is mounted to the catheter 280 by connection to housing290. Housing 290 is connected to port 282 via a barbed fitting 295providing an interference fit with the port 282. The hub 300 is lockedor secured to connector 290 such as by a snap fit provided by the latcharms discussed below, although other attachments are also contemplatedsuch as a friction fit, threaded attachment, other form of latch, etc.,as well as other types of snap fits to provide an attachment thatmaintains an airtight seal so the air is contained within the air lumenand balloon 92 of the catheter 280. (As noted above catheter 280 isidentical to catheter 200 except for its connector so catheter 280includes (not shown) the inner and outer pressure balloons, stabilizingballoon, temperature sensor, etc. The catheter 280 can also have asingle balloon as in the aforementioned embodiments).

The housing 290 attached to catheter 280 has a proximal opening 294 anda channel (lumen) 296 to receive an elongated (rod-like) member or nose302 extending distally from transducer hub 300. As shown channel 296 hasa first diameter region 296 a to match with the lumen 283 of the port282, a second larger diameter region 296 b proximal of region 296 a toreceive the male rod 302 of the hub 300, and a still larger diameterregion 296 c proximal of region 296 b to receive the valve 299 and valve298 and allow expansion thereof. As shown, valve 298 is dome shaped andis distal of valve 299. Conical cap 293, proximal of valve 299, providesa lead in to the valve 299 for the rod 302. Thermistor pins 292 receivethermistor connectors 308. Note valves 288, 299 are one example ofvalves that can be provided as other valves to provide an airtight sealare also contemplated.

Hub 300 is mounted to connector 290 and includes a housing 304 fromwhich a pair of distally extending snap fit connector arms 306 extend.The arms 306 are sufficiently flexible to enable attachment and have anenlarged distal portion 307, illustratively shown as arrow shapedalthough other enlarged shapes could be provided. The elongated member302 extends between the connector (latch) arms 306. When the hub 300 ismounted to the connector 290, the elongated member 302 extends into thechannel 296 to advance air to inflate the inner balloon. The enlargedends 307 of latch arms 306 enter recesses 291 of connector 290 andengage shoulders 291 a to retain the hub 300. Note to release the hub300, the ends 307 of latch arms 306 are pressed radially inwardly todisengage from shoulder 291 a and the hub 300 is pulled proximally.

The housing (connector) 290 has a lumen 296 for communication with thelumen 283 in the side port 282 of catheter 280 which communicates withthe air lumen and inner balloon of the catheter 280. As noted above, thelumen 296 is dimensioned to receive the elongated rod 302 of transducerhub 300. The wire for the sensor extends in housing 300. When transducerhub 300 is attached to connector 290, such attachment inserts theelongated rod 302 into lumen 296 to advance air though the air lumen inthe catheter and into the balloon 204. (Note the air lumen extends intoits angled side port 282). The elongated member 302 also has a channelor lumen 305 extending therethrough to allow the pressure wave to travelthrough to the pressure sensor. Although in preferred embodiments noadditional air needs to be injected into balloon 204 after attachment ofhub 300, it is also contemplated that a port or opening can be providedin hub 300 to receive an injection device for injection of additionalair. Such additional air can communicate with and flow through channel305 of elongated member 302, into the air lumen and balloon 204 forinflation, or alternatively, a side port or opening in the angled portdownstream of the elongated member 302 could be provided. Attachment ofhub 300 to housing 290 also automatically connects thermistor connectors308 to thermistor pins 292 to automatically connect the temperaturesensor to the hub 300 for communication via a cable to a temperaturemonitor.

To charge the system, when the hub 300 is mounted to the side port 282via attachment to connector 290, the elongated member 302 extends intolumen 296 to advance air through the air lumen into balloon 204 (or thepressure balloon in the embodiments with a single pressure balloon) toexpand the balloon 204. That is, connection of the transducer hub 300 tothe catheter 280 (port 282) automatically advances air through theconnector lumen 296, the port lumen 283 and the first lumen 96 to expandthe balloon 204. (Such connection also automatically connects thetemperature sensor to the hub 300). In some embodiments, 0.2 cc of aircan be displaced/advanced by the member 102, although other volumes arealso contemplated. Thus, as can be appreciated, mounting of the hub 300to the catheter 280 automatically pressurizes the air lumen/chamber andexpands the balloon. Note the balloon can be partially or fully inflated(expanded), dependent on the amount of air advanced into the balloon.Further note that the lumen is not vented to atmosphere when thetransducer hub 300 is attached and air is advanced through the airlumen. The port 282 includes a closable seal, e.g. valves 298 and 299,through which the elongated member 302 is inserted but maintains theseal when the elongated member 302 remains in the lumen 296. Note thatcatheter 290 is identical in all other respects to catheter 200 so thatthe description of catheter 200 and its components and function arefully applicable to catheter 280, the only difference being theconnector 290 of catheter 292 to receive transducer hub 300. The hub 300also differs from hub 240.

In the alternative embodiment of FIGS. 29A-29C, the latch arms arereversed so that they are located on the connector rather than on thetransducer hub as in FIG. 28A. More specifically, transducer hub(housing), designated by reference numeral 320, has an elongated member322 with a channel 323 and is identical to elongated member 302 of FIG.28A for advancing air through the lumen and into the pressure balloon.Pressure transducer 324 is contained within the housing 320. Recesses325 are dimensioned to receive the latch arms 317 of the connector orhousing 310 which is connected to the side port 282 of catheter 280.(Catheter 280 is the same as catheter 280 of FIG. 28A except forconnector 310). Extending proximally form housing 310 are two latch arms316 with enlarged region 317 which engage the shoulders 326 formed byrecesses 325 in hub 320 in a similar manner as latch arms 306 of FIG.28A engage in recesses 291 and shoulder 291 a, Connectors 328 in hub 320engage thermistor pins 312 of connector 310 for connection of thetemperature sensor. Connection of the hub 320, like hub 300,automatically advances air to inflate the pressure balloon andautomatically connects the temperature sensor.

To disconnect the hub 320, ends 317 of latch arms 316 are pressedradially inwardly to disengage from shoulder 326 so hub 320 can bepulled proximally out of connector 310.

Note the lumen which is used to inflate the pressure balloon and createthe air column has an opening at a distal region to communicate with theinterior of the pressure balloon. If an outer balloon is provided, anadditional lumen would be provided in the catheter to communicate withthe outer balloon to fill the outer balloon and an additional angledport (extension) at the proximal end of the catheter would receive aninflation device to inflate, either fully or partially, the outerballoon.

Note in each of the embodiments disclosed herein, air is described asthe preferred gas for creating the column and expanding the balloon,however, other gasses are also contemplated for each of the embodiments.

The pressure balloon can be symmetrically shaped as shown in some of theembodiments or alternatively shaped such that a distal region has anouter transverse cross-sectional dimension, e.g., diameter, greater thanan outer transverse cross-sectional dimension, e.g., diameter, of theproximal region. A smooth transition (taper) can be provided between thedistal region and proximal region, although other configurations arealso contemplated. The inner (and outer) balloon can by way of examplebe made of urethane, although other materials are also contemplated.

The wire connector of the foregoing embodiments can plug into theopenings of a connector positioned on or in the transducer hub. The wireconnector can be internal of the hub with an opening in the wall of thehub to enable access for the wire connector. Also note thatalternatively the wire can include a female connector and the hub canhave a male connector. Other types of connectors/connections are alsocontemplated.

In alternate embodiments, any of the catheters disclosed here caninclude a pulse oximetry sensor to measure oxygen saturation in theurethral or bladder tissue. The sensor can be located either proximal ordistal to the pressure balloon and/or stabilizing balloon. It could alsoalternatively be mounted within one of the balloons. A separate channel(lumen) could be provided for such sensor and wires.

In alternate embodiments, any of the catheters disclosed herein caninclude an additional channel (lumen) for continuously recordingmaternal PO2 and/or maternal respiration. Additionally, in alternateembodiments, any of the catheters disclosed herein can include a channel(lumen) for a sensor measuring fetal heart rate. Note each of thevarious sensors for measuring different parameters and their associatedwires (unless wireless) can be provided in separate channels, oralternatively, one or more sensors and their associated wires can beprovided in a single channel to reduce the overall size/diameter of thecatheter. Thus, for example, a catheter with five or six lumens could beprovided as follows: 1) lumen for expansion of outer balloon; 2) lumenfor expansion of inner balloon and for pressure reading; 3) lumen fordrainage of the bladder to a drainage bag; 4) lumen for expansion of theretention balloon; 5) lumen for the acoustic sensor to assess fetalheart rate; and 6) lumen for the pulse oximeter to measure maternaloxygen levels.

It is also contemplated that a backup system be provided to determinepressure. The backup system can provide a double check of pressurereadings to enhance accuracy. Such backup system can be used with any ofthe embodiments disclosed herein to provide a second pressure readingsystem. One example of such backup system is disclosed in FIGS. 14A and14B. In this embodiment, catheter 160 has the pressuretransducer/pressure sensor 162 like sensor 30 of FIG. 1 within the air(or other gas) lumen 164 communicating with pressure balloon 167,forming a “first system”, plus a pressure transducer/pressure sensor 169at a proximal end of the catheter as in FIG. 12 or external of thecatheter forming a “second system”. Thus, the pressure sensor 162 is ata distal end of the air charged lumen 164 and pressure sensor 169 is atproximal end of the air charged lumen 164. Both sensors 162 and 169 areelectrically connected to a monitor which provides a graphic display ofpressure readings. The catheter 160 also includes a temperature sensoreither as part of the sensor 162 or a separate component that can bepositioned for example in the lumen 164 distal of sensor 162 as in theembodiment of FIG. 8. A stabilizing balloon 168 and an inflation lumento inflate balloon 168 can also be provided. Lumen 163, having a sideopening 170 at its distal end, is configured to drain the bladdersimilar to lumen 20 and side opening 22 of the embodiment of FIG. 1.

In use, catheter 160 is inserted into the bladder and stabilizingballoon 168 is inflated to secure the catheter 160 in place. The systemis charged by inflation of the balloon 167, i.e., preferably partiallyinflated for the reasons discussed above, by insertion of air throughside port 172 which is in fluid communication with the air lumen in aclosed system formed by the internal space of the balloon 167 and theinternal lumen 164 communicating with the internal space of balloon 167.With the balloon 167 inflated, pressure monitoring can commence asexternal pressure applied to an outer surface of the balloon 167compresses the air (or other gas) within the chamber. The sensor 162 atthe distal end of lumen 64 provides continuous pressure readings,converted to an electrical signal by the transducer within the distalend of the lumen, and then electrically communicates through itstransmission wires extending through the air lumen to an externalmonitor either directly or via a converter. Additionally, pressurewithin the air charged column is measured at a proximal region by sensor169 within side port 172 of catheter 160. The sensor 162 at the distalend of lumen 164 provides continuous pressure readings, and suchpressure readings can be confirmed by the proximal sensor. Such pressurereadings can be performed continuously (along with continuoustemperature monitoring) or alternatively can also be adapted if desiredfor periodic monitoring so the pressure and/or temperature readings canbe taken at intervals or on demand by the clinician. Thus, air pressurereadings at a proximal end plus microtip pressure readings at the distalend are provided. The sensors 162 and 169 can electrically communicatewith an external monitor to display both pressure readings from sensors162, 169, or alternatively, if the pressure readings are different, theycan be averaged to display a single measurement. Clearly, other displaysof information can be provided to display the information from the twosensors 162, 169.

The sensors disclosed herein can be microtip sensors within the airlumen or balloon. In alternative embodiments, fiber optic sensors withinthe air lumen or within or around the balloon can by utilized totransmit circumferential/area pressure exerted on the bladder. Thepressure transducers can be housed within the catheter or alternativelyexternal to the catheter. Additionally, core temperature sensors can bepart of the pressure sensor or a separate axially spaced component.

The multi-lumen catheters disclosed herein provide an air (or other gas)charged balloon giving precise readings of uterine contraction pressureand core temperature and the systems are charged via insertion of airthrough a side port via a syringe in a gross fashion or throughdisplacement of air in the lumen. The multi-lumen catheters are easilyinserted into the bladder in the same manner as standard bladderdrainage catheters and enable continuous drainage of urine whilecontinuously recording uterine contraction pressure without interruptingurine flow and without requiring retrograde filling of the bladder withwater. Thus, these catheters provide a closed system. The catheters alsohave a balloon providing a large reservoir (large capacity) and largecircumferential area/interface for obtaining more information from thebladder over multiple reference points (rather than a single pointsensor) that provides an average pressure to provide a gross measurementand a more accurate assessment of the surrounding environment aspressure measurement is not limited to one side of the bladder but candetermine measurements on the opposing side as well.

As noted above, the catheters, i.e. the transducer, can be connected toa bedside monitor through either a wire or blue-tooth wirelessconnection. Such wireless connection would provide the patient theoption to ambulate while in labor.

The system can also include an indicator or alarm system to alert thestaff at the site as well as remote staff through wired or wirelessconnections to external apparatus, e.g., hand held phones or remotemonitors.

As noted above, an alarm or indicator can be provided in someembodiments to alert the staff. The indicator can be a visual indicatorsuch as a light, LED, color change, etc. Alternatively, or additionally,the indicator can be an audible indicator which emits some type of soundor alarm to alert the staff. The indicator can be at the proximal regionof the catheter or at other portions of the catheter, e.g., at a distalend portion, where known imaging techniques would enable the user todiscern when the indicator is turned on. It is also contemplated that inaddition to providing an alert to the user, the pressure or othermonitoring system can be tied into a system to directly controlparameters so that if the pressure or other parameter is outside adesired range, appropriate steps can be taken. In such systems, one ormore indicators can be provided on the proximal portion of the catheter,e.g., at a proximal end outside the patient's body, or separate from thecatheter. The sensor(s) is in communication with the indicator(s),either via connecting wires extending through a lumen of the catheter ora wireless connection. The sensor(s) can be part of a system thatincludes a comparator so that a comparison of the measured pressure orother parameter, e.g., maternal core body temperature, maternal PO2levels, fetal heart rate, etc. to a predetermined value is performed anda signal is sent to the indicator to activate (actuate) the indicator ifthe measured pressure value or other value is exceeded, thereby alertingthe clinician or staff that pressure or other parameters are outsidedesired ranges and a signal is also sent to a device or system toautomatically actuate the device or system to make the necessaryadjustments. If the measured value is below the threshold, the indicatoris not activated.

As noted above, the catheters of the present invention can be insertedin the same manner as the regular urinary bladder drainage catheter.Thus the catheters do not require any special nursing or physicianskills for insertion and use. Thus, the catheters can be easily insertedby any provider on labor and delivery ward with the skills to insert asimple bladder drainage catheter.

As noted above, the catheters may be used to precisely detectcontractions in mothers with symptoms of preterm labor. They can be usedto detect adequacy of labor in mothers that are not normally progressingin labor. They can be used to help detect pressure in mothers presentingwith signs of pre-eclampsia (PE). It has been found that detection ofpressure in patients with PE can help diagnose and prevent maternalhealth complications or death. In some embodiments as noted above,specialized sensors in the catheter will help detect maternaloxygenation which is important to monitor in all laboring patients. Thecatheters as noted above can in some embodiments also have thecapability to detect maternal respiration and/or fetal heart rate. Thecatheters in some embodiments can have an acoustic sensor to pick upfetal heart tones.

It is also contemplated that a micro-air charged sensor could beprovided in the retention (stabilizing) balloon to help detect fetalheart rate.

It is also contemplated that microtip sensors and/or fiber optic sensorscan be utilized to measure pressure, and these sensors can be utilizedinstead of the air pressure readings utilizing the aforedescribedballoon(s) for measuring pressure.

The catheters disclosed herein are designed for insertion into thebladder. However, it is also contemplated that they can be adapted forinsertion into other body regions.

Although the apparatus and methods of the subject invention have beendescribed with respect to preferred embodiments, those skilled in theart will readily appreciate that changes and modifications may be madethereto without departing from the spirit and scope of the presentinvention as defined by the appended claims.

What is claimed is:
 1. A multi-lumen catheter for monitoring uterinecontraction pressure, the catheter comprising: an expandable outerballoon at a distal portion of the catheter, the outer balloon having afirst outer wall; an expandable inner balloon positioned within theouter balloon, the inner balloon having a second outer wall; a firstlumen communicating with the inner balloon, the inner balloon and firstlumen forming a gas filled chamber to monitor pressure within a bladderto thereby monitor uterine contraction of the patient, wherein the outerballoon has a circumferential area greater than a circumferential areaof the inner balloon, wherein in response to pressure within the bladderexerted on the first outer wall of the expanded outer balloon, the outerballoon deforms and exerts a pressure on the second outer wall of theexpanded inner balloon to deform the inner balloon and compress the gaswithin the inner balloon and the first lumen to provide a finermeasurement; a second lumen communicating with the bladder to removefluid from the bladder; and a pressure transducer for measuring bladderpressure based on gas compression caused by deformation of the expandedinner balloon deformed by the expanded outer balloon, the bladderpressure providing an indication of uterine contraction pressure.
 2. Thecatheter of claim 1, wherein the outer balloon has a circumferenceengageable with a wall of the bladder at multiple contact regions toprovide multiple reference points for calculation of an average pressureof the bladder wall.
 3. The catheter of claim 1, wherein the pressuretransducer is contained within a hub and the hub includes an elongatedmember extending distally therefrom, and connection of the pressuretransducer to a first port of the catheter automatically inserts theelongated member into the first lumen to advance air into the innerballoon to expand the inner balloon, the pressure transducercommunicating with the air filled chamber.
 4. The catheter of claim 3,wherein the first lumen is not vented to atmosphere when the pressuretransducer is connected to the catheter and advances air to expand theinner balloon.
 5. The catheter of claim 1, wherein the second lumen hasa side opening distal of the inner and outer balloons.
 6. The catheterof claim 1, wherein the second lumen has a side opening proximal of theinner and outer balloons.
 7. The catheter of claim 1, wherein thecatheter further comprises a third lumen communicating with the outerballoon to expand the outer balloon.
 8. The catheter of claim 1, whereinthe catheter has one or more of a temperature sensor positioned tomeasure core body temperature, a fetal heart rate sensor to measure corebody temperature, and a PO2 sensor positioned to measure PO2 levels. 9.The catheter of claim 3, further comprising a temperature sensor and awire extending proximally from the temperature sensor, and the hub has afirst opening to receive a connector of the wire to automaticallyconnect the temperature sensor to a cable extendable from the hub andconnectable to an external temperature monitor.
 10. The catheter ofclaim 1, further comprising a stabilizing balloon proximal of the outerballoon for stabilizing the catheter, and the catheter includes anadditional lumen communicating with the stabilizing balloon to expandthe stabilizing balloon.
 11. The catheter of claim 3, wherein afterinitial advancement of air into the first lumen by the elongated memberupon connection of the pressure transducer, additional air does not needto be inserted during the duration of insertion of the catheter in abody of a patient.
 12. The catheter of claim 1, wherein the outerballoon has a distal region having a larger transverse cross-sectionthan a proximal region.
 13. A multi-lumen catheter for monitoringuterine contraction pressure, the catheter comprising: a distal balloonat a distal portion of the catheter; a first lumen communicating withthe distal balloon, the distal balloon and first lumen forming an airfilled chamber to monitor pressure within a bladder to thereby monitoruterine contraction pressure of a patient, wherein in response topressure within the bladder the distal balloon deforms to compress theair within the distal balloon, the first lumen having a first proximalport communicating with the first lumen; a second lumen communicatingwith the bladder to remove fluid from the bladder; and a hub connectableto the first port of the catheter, the hub including a pressuretransducer for measuring pressure based on air compression with thefirst lumen, and an elongated member extending distally from the hub,wherein connection of the hub to the first port automatically insertsthe elongated member into the first lumen to advance air through thefirst lumen to expand the distal balloon, the first lumen not vented toatmosphere when the hub is connected to the first port so the firstlumen remains sealed to outside air during expansion of the distalballoon.
 14. The catheter of claim 13, further comprising a and atemperature sensor positioned in the catheter and having a wireextending through the catheter, wherein connection of the hub to thefirst port automatically connects the wire to an electrical connector inthe hub for connection to a temperature monitor.
 15. The catheter ofclaim 14, further comprising a stabilizing balloon proximal of thedistal balloon for stabilizing the catheter.
 16. The catheter of claim15, wherein the second lumen has a side opening between the distalballoon and the stabilizing balloon.
 17. The catheter of claim 14,wherein the catheter includes one or both of a fetal heart rate sensorand a PO2 sensor.
 18. A method for measuring uterine contractionpressure comprising the steps of: providing a catheter having first andsecond lumens, an expandable first balloon, an expandable second balloonpositioned over the first balloon, and a temperature sensor; insertingthe catheter into a bladder of a patient; connecting a hub containing apressure transducer to the catheter to automatically advance air throughthe first lumen of the catheter to expand the first balloon from adeflated condition to a more expanded condition; obtaining a firstpressure reading of the bladder based on deformation of the firstballoon caused by deformation of the second balloon in response tobladder pressure exerted on the second balloon, the bladder pressuremeasurement providing an indication of uterine contraction pressure;transmitting the first pressure reading to an external monitor connectedto the hub to assess uterine contraction pressure; obtaining a secondpressure reading of the bladder based on deformation of the firstballoon caused by deformation of the second balloon in response tobladder pressure exerted on the second balloon; and transmitting thesecond pressure reading to the external monitor connected to the hub toassess uterine contraction pressure.
 19. The method of claim 18, whereinthe step of connecting the hub automatically connects the temperaturesensor to a connector within the hub.
 20. The method of claim 18,further comprising the step of measuring one or both of fetal heart rateand maternal PO2 levels.